Does the role of minor-mode-alist variable is to only help in displaying the mode name?

Does the role of minor-mode-alist variable is to only help in displaying the mode name?

[Talespin Kit]

In the elisp document the role of the minor-mode-alist variable is described as below. 


23.3.1 Conventions for Writing Minor Modes
----------------------------------------------------------------

 Add an element to `minor-mode-alist' for each minor mode (*note
     Definition of minor-mode-alist::), if you want to indicate the
     minor mode in the mode line. 

But the function "describe-mode" uses the variable "minor-mode-alist" to find the list of minor modes. Does this mean the document is to be updated. Because it gives the impression the information about the minor modes are stored somewhere else. Although i am not able to find it out. 

Regards,
Talespin

Re: Does the role of minor-mode-alist variable is to only help in displaying the mode name?

[W. Greenhouse]

Talespin Kit <talespin_kit-/E1597aS9LQAvxtiuMwx3w@public.gmane.org> writes:

> In the elisp document the role of the minor-mode-alist variable is
> described as below.
>
>
> 23.3.1 Conventions for Writing Minor Modes
> ----------------------------------------------------------------
>
>  Add an element to `minor-mode-alist' for each minor mode (*note
>      Definition of minor-mode-alist::), if you want to indicate the
>      minor mode in the mode line. 
>
> But the function "describe-mode" uses the variable "minor-mode-alist"
> to find the list of minor modes. Does this mean the document is to be
> updated. Because it gives the impression the information about the
> minor modes are stored somewhere else. Although i am not able to find
> it out.

Yes, `describe-mode' uses `major-mode' to discover which major mode's
documentation to show and `minor-mode-alist' to discover which minor
modes' documentation to show.  There is no other listing of enabled
minor modes.  It should therefore be considered not merely a breach of
convention but a serious design flaw if a major or minor mode fails to
set these variables.  Fortunately, most major modes are created with
`define-derived-mode' and most minor modes with `define-minor-mode',
which take care of these and other mode-related bureaucratic tasks
automatically.

Perhaps the language of (info "(elisp) Minor Mode Conventions") could be
strengthened to match that of (info "(elisp) Major Mode Conventions"),
which says:

--8<---------------cut here---------------start------------->8---
   * The major mode command should set the variable `major-mode' to the
     major mode command symbol.  This is how `describe-mode' discovers
     which documentation to print.
--8<---------------cut here---------------end--------------->8---

Hope that clarifies things a bit.